This invention relates generally to pocketed spring assemblies for mattresses, cushions and other bedding or seating products and, more particularly, to a posturized pocketed coil spring assembly and associated method of manufacturing such an assembly.
A well known type of bedding or seating product comprises a spring assembly which includes a number of discrete coil springs, each of which is enclosed in a fabric pocket in a length of folded fabric material. Longitudinal axes of the coil springs are generally parallel with one another so that the top and bottom end turns of the coil springs define top and bottom faces of the spring assembly. A row of such pocketed springs is known in the industry as a string of pocketed springs. A bedding or seating product can be fabricated from such strings of pocketed springs by binding or adhering the individual rows or strings of pocketed springs together to form a spring assembly which may be padded and encased in an upholstered covering. U.S. Pat. No. 6,143,122, which is fully incorporated herein, discloses one such method of adhesively bonding strings of pocketed springs together to form a spring assembly.
This type of spring assembly is commonly referred to as a pocketed spring assembly due to the fact that each spring is contained within an individual pocket of fabric material. The construction of strings of pocketed coil springs in each pocket is well known in the art and, for example, is disclosed in U.S. Pat. No. 4,439,977 which is hereby incorporated by reference in its entirety. The system disclosed in that patent includes a spring coiler which forms a coil spring which is subsequently compressed and inserted between the plies of folded pocketing fabric material. Other systems for manufacturing pocketed coil spring assemblies are disclosed in PCT Patent Application No. WO 94/18116 and U.S. Pat. No. 6,101,697, each of which are expressly incorporated herein by reference.
Pocketed spring assemblies are generally recognized to have a unique and particular luxurious feel to them and mattresses manufactured of such pocketed spring assemblies provide a feeling of softness without lacking spring resilience or support. Mattresses and similar articles constructed of pocketed spring assemblies are often considered a high-end type of product because of the added benefits and features of the pocketed coil springs. Mattresses and the like of this type can be more costly to manufacture and assemble as a result of the considerable amount of time and labor which is involved in their manufacture, together with the fact that the method of fabrication and assembly of such pocketed spring assemblies can be complicated, particularly in an automated process.
One particular aspect of pocketed spring assemblies and the associated mattresses or the like is that the resulting product may have a xe2x80x9chardxe2x80x9d feel due to the fact that all of the coil springs are identical and compressed to the same degree in individual pockets. Usually, the firmness of such a product is uniform across the width and along the length of the product.
Additionally, while pocketed spring assemblies desirably provide a combination of softness and support, the ability to economically posturize a spring assembly or mattress of pocketed spring coils has heretofore been difficult. Posturization provides multiple zones or sections of differing firmnesses within a product such as a mattress. For example, the middle regions of the mattress, which typically support a person""s torso, often require a firmer more resilient support while other areas of the mattress which support the feet and head of a person require a softer feel.
One known method of posturizing a pocketed spring unit has been to incorporate springs made of different gauge wire into the strings of springs. For example, the springs incorporated into the strings of springs within certain sections or zones of the spring assembly are made of a larger gauge wire than the springs incorporated into the strings of springs of the other sections or zones of the spring assembly. U.S. Pat. No. 6,173,464 discloses this concept, albeit with continuous bands of springs as opposed to individual springs.
Another method of posturizing a spring assembly made of conventional coil springs, as opposed to pocketed coil springs incorporated into strings of pocketed springs, is to place filler material such as urethane foam on top of the shorter springs of the spring assembly. Applicant""s U.S. Pat. No. 6,353,952, incorporated by reference herein, discloses a bedding or seating product made in such a manner. However, this method has heretofore been used only with unpocketed coil springs.
Therefore, there is a need for a posturized pocketed spring assembly and associated method of manufacture which offers the advantages of posturization of the pocketed spring assembly without the higher manufacturing costs, production difficulties and inefficiencies associated with known posturized pocketed spring assemblies.
There is further a need to provide a posturized bedding or seating product utilizing strings of pocketed springs of differing heights so as to impart differing degrees of firmness to different sections of the product.
The invention of this application comprises a pocketed bedding or seating product and associated method of manufacture. The bedding or seating product comprises a pocketed spring assembly, filler materials, one or more pads and an upholstered covering surrounding the pocketed spring assembly, filler material and pads.
The pocketed spring assembly comprises a plurality of parallel strings of springs joined together. Each of the strings of springs comprises a plurality of interconnected pocketed coil springs. Each of the pocketed coil springs comprises a spring surrounded with a pocket of fabric, as is conventional. The springs are typically coil springs, but may be other types of springs. Each of the coil springs has an upper end turn, a lower end turn and a plurality of central convolutions between the end turns.
Preferably, each string of springs is made of one piece of fabric folded and welded into a plurality of pockets, each of the pockets containing a coil spring. Opposed plies of fabric of the string of springs may be joined together by sewing, gluing or sonic welding, as known in the art. Adjacent pockets within a string of springs are separated by one or more generally vertically oriented lines of attachment or seams of the opposed plies to each other. The height of the pocket is determined by the distance between the bottom of the pocket and one longitudinal segment of attachment or seam of the opposed plies to each other. Alternatively, the height of the pocket may be determined by the distance between top and bottom seams of the pocket.
The bedding or seating product typically has a longitudinal dimension and a transverse dimension, the longitudinal dimension being greater than the transverse dimension. However, the longitudinal dimension and transverse dimension may be identical in a square bedding or seating product. In the invention of the present application, the strings of springs may extend longitudinally or transversely, depending upon the desired effect.
Adjacent strings of springs of the bedding or seating product are preferably glued together but may be otherwise secured to each other. At least one border wire may extend around the perimeter of the pocketed spring assembly of the bedding or seating product and be secured to select outermost pocketed coil springs. A first or lower border wire may be secured to the lower end turns of the coil springs of the outermost strings. A second or upper border wire may be secured to the upper end turns of the coil springs of the outermost strings or, alternatively, either border wire may be secured to intermediate convolutions of the coil springs of the outermost strings of springs.
In each embodiment of the present invention, the bedding or seating product is posturized such that certain regions or portions of the product are firmer than other areas or portions of the product. This may be accomplished by grouping together multiple strings of springs having identical characteristics in one region of a bedding or seating product. The strings of springs of the other regions may have different characteristics so as to impart different firmnesses to the different regions.
In at least one preferred embodiment of the present invention, the pocketed spring assembly has multiple sections or regions of differing firmnesses, each section or region comprising multiple identical strings of springs joined together. In at least one section of the pocketed spring assembly, each string of springs has pockets of an identical first height along its length. In at least one other section of the pocketed spring assembly, each string of springs has pockets of an identical second height along its length. The second height is greater than the first height. For purposes of this application, the strings of springs having pockets of a first height will be considered short strings of springs and the strings of springs having pockets of a second height will be considered tall strings of springs. Filler material is located above the short strings of springs. The filler imparts a softer feel to the user than does the tall strings of springs. Consequently, the sections or regions of the product comprising short strings of springs (those of a first height) and filler above such strings of springs are of a lesser firmness than the firmness of the other sections comprising tall strings of springs (those of a second height). In such embodiments, the strings of springs may extend longitudinally or transversely, depending upon the desired effect.
In several preferred embodiments of the present invention, the filler is of a third height so that when placed upon the springs of a first height, the sum of the first and third heights is approximately equal to the height of the tall strings of springs, i.e., the second height. In such a manner, the bedding or seating product has a uniform upper surface comprising the upper surfaces of the tall strings of springs and the upper surface of the filler.
The filler may be numerous structures and/or materials, including but not limited to pieces of urethane foam, various fibrous materials, air bladders or water bladders or even matrixes of short springs contained in cloth fiber pockets.
In another preferred embodiment the tall strings of springs of a second height extend above and below the short strings of springs of the pocketed spring assembly. In this embodiment, filler is located both above and below the short strings of springs. The upper and lower surfaces of the filler are generally coplanar with upper and lower surfaces of the tall strings of springs, respectively.
In other preferred embodiments of the present invention, strings of springs having pockets of differing heights are incorporated into a pocketed spring assembly. Applicant""s U.S. patent application Ser. No. 10/307,883 filed Dec. 2, 2002 entitled xe2x80x9cPocketed Bedding or Seating Product Having Pockets of Alternating Heightsxe2x80x9d, which is fully incorporated by reference herein, discloses such strings of springs incorporated into a pocketed spring assembly. In each of these preferred embodiments, at least several strings of springs have pockets of a first height and pockets of a second height greater than the first height. Filler is located only above the pockets of a first height in accordance with the present invention.
In another preferred embodiment of the present invention, tall pockets of the strings of springs are located in a generally rectangular pattern in the middle of the bedding or seating product, and short pockets of the strings springs (pockets of a lesser height than the pockets in the middle of the product) are arranged around the perimeter of the generally rectangular section of tall pockets. Filler is placed above the short pockets around the perimeter of the bedding or seating product in order to provide a softer feel to the user around the perimeter than in center of this embodiment of product.
In another preferred embodiment of the present invention, a section of short pockets are arranged in a generally rectangular pattern in the middle of the bedding or seating product. Tall pockets (pockets of a greater height than the pockets in the middle section of the product) are arranged around the perimeter of the generally rectangular section of short pockets. Filler is placed above the short pockets in the middle of the bedding or seating product. The tall pockets provide an edge support around the perimeter of the product which is of a greater firmness than the central section or core of the product.
In any of the preferred embodiments of the present invention, the springs may be identical before being inserted into the pockets of the strings of springs. However, once inside the pockets, the springs in the shorter pockets may be compressed more than the springs in the taller pockets. Conversely, the springs may be of different heights before being inserted into the pockets of the strings of springs. Alternatively, the coil springs may have different physical characteristics such as heat treatment, pitch, coil diameter, etc. before being placed in the pockets.
One method of manufacturing the pocketed spring assembly of the present invention comprises inserting at least one spring into each of the pockets of a string of springs. The pockets are then closed such that selected pockets within the string of springs is of a height less than other pockets in the string of springs. The strings of springs are then joined together to form the pocketed spring assembly. Filler is placed above selected pockets of at least some of the strings of springs. The pocketed spring assembly and filler are encased in an upholstered covering.
The method of manufacturing the posturized spring assembly of the present invention varies depending upon the desired posturization. However, in each of the applications of the present invention whenever pockets of differing heights are incorporated into a portion of a string of springs, at least one region or section of the pocketed spring assembly has an initial xe2x80x9csoftxe2x80x9d feel when a load is placed thereon.
In each of the embodiments of the present invention, incorporating pockets of different heights into at least several strings of springs results in a posturized pocketed spring assembly after multiple strings of springs are joined to each other. Such a product may be made in accordance with a customer""s needs and desires quickly and easily.
These and other objects and advantages of the present invention will be more readily apparent from the following drawings.